Many places will be snow that falls down after a while become heavily polluted, especially in snowy densely populated areas, such as major cities in climate zones with significant snowfall in winter. A typical example is Oslo, Norway's capital, where urban traffic means that snow quickly becomes highly polluted. It has been customary to dump such polluted snow in the Oslo fjord, whereupon the pollution has been clearly visible, especially in the inner Oslo harbour. Alternatively, snow has been dumped on its own landfills, which unfortunately have often been near valuable river systems, with resulting severe pollution of waterways. One problem is where to contain the contaminated snow, but a more serious problem is how to avoid pollution of the fjord, rivers and ground around the landfill sites. There are commercially available systems for melting snow, such as the plants designated as Snow Dragon. However, there is little or no cleaning integrated with such systems, at best it is only a question of retention of heavy and large particles. Capacity is limited, as it is necessary that the snow is light and airy, and fuel consumption is high. For the time being most of the snow that lay down in the streets of Oslo city is gathered together and driven away in trucks to a facility some distance outside downtown. During and after heavy snowfalls heavy traffic of diesel-powered trucks are idling and waiting for a long time before they have emptied their loads, after which the cars drive back to the city centre to upload new contaminated snow and ice. The emissions of diesel and other contaminants are considerable, and there is no regular cleaning of the snow that is deposited, so that all pollutants are collected in the ground, flows into waterways or into groundwater reservoirs over time, and some leakage to air will also take place. Also, the collected snow typically contains significant amounts of garbage that is revealed as the landfill is melting in the summer season. It is proven that even snow that is considered to be pure, i.e. a maximum of one or two days old after a snowfall, is so heavily contaminated that nearby rivers can be classified as “very heavily polluted”. In the city of Oslo there is now a requirement that all snow older than two days must be collected and deposited, but the landfill has as mentioned no self-cleaning and the transport involves considerable pollution. In addition, the snow can be highly polluted, although it is classified as plain, which is younger than two days old. There is a need for a plant and a method, which completely or in part solve the above mentioned problems, that is to reduce pollution from contaminated snow and the handling thereof.